Esterification of cellulose with carbonic carboxylic anhydrides

ABSTRACT

-O-CO-O-CO-A&#39;&#39;   WHEREIN A&#39;&#39; IS POLYFLUOROALKYL OR POLYFLUOROALKOXYALKYL, R&#34; IS A LOWER ALKYLENE GROUP, AND G&#39;&#39; IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND   A&#39;&#39;-CO-O-CO-O-R&#34;-G&#39;&#39;   WHEREBY A MONOVALENT OR DIVALENT CARBON ACYL GROUP IS BONDED TO THE CELLULOSE BY REPLACING ACTIVE HYDROGEN, WITH CONSEQUENT ESTER FORMATION, AND THERE IS RELEASED AS BY-PRODUCTS AN ALCOHOL OR GLYCOL AND CARBON DIOXIDE. IN ADDITION, NOVEL COMPOUNDS OF THE CARBONIC CARBOXYLIC ANHYDRIDE CLASS WHICH ARE USEFUL IN THE FORMATION OF CELLULOSE ESTERS ACCORDING TO THE ABOVE-MENTIONED PROCESS, AND WHICH ARE CHARACTERIZED BY THE FORMULA   -CO-O-CO-O-   A PROCESS FOR ESTERIFICATION OF CELLULOSE WHEREIN A CELLULOSIC MATERIAL IS REACTED UNDER MILD CONDITIONS AND IN THE ABSENCE OF A CATALYST WITH MIXED CARBONIC CARBOXYLIC ANHYDRIDES HAVING THE CHARACTERISTIC GROUP

United States Patent Oihce US. Cl. 260-224 15 Claims ABSTRACT OF THE DISCLOSURE A process for esterification of cellulose wherein a cellulosic material is reacted under mild conditions and in the absence of a catalyst with mixed carbonic car boxylic anhydrides having the characteristic group ooo whereby a monovalent or divalent carbon acyl group is bonded to the cellulose by replacing active hydrogen, with consequent ester formation, and there is released as by-products an alcohol or glycol and carbon dioxide.

In addition, novel compounds of the carbonic carboxylic anhydride class which are useful in the formation of cellulose esters according to the above-mentioned process, and which are characterized by the formula R" is a lower alkylene group, and G is selected from the group consisting of hydrogen and The present invention relates to a process which modifies cellulose or other hydroxyl-containing polymers by replacing the active hydrogen atoms of the hydroxyl groups with a divalent or monovalent carbon acyl radical. It relates as well to certain compounds useful in such process.

More particularly, the present invention relates to such a process as referred to above wherein the hydroxylcontaining polymer is subjected to esterification by one or more mixed carbonic carboxylic anhydrides.

The varied esters of cellulose are widely recognized to be valuable compounds, especially in the manufacture of textiles and films. Prior methods for esterification of cellulose generally require reaction conditions which tend to damage the substrate material or to lead to undesirable by-products, such as acid. It is a primary object of the present invention, therefore, to provide a process for esterifying hydroxylated polymers such as cellulose which can be carried out under mild conditions and without creation of undesirable by-products.

More particularly, it is an object of the present invention to provide a process for the esterification of an hydroxylated polymer which is efiicient, and which will readily take place under relatively mild, neutral conditions, without a catalyst, and without formation of acidic by-products.

It is a further object of the present invention to provide a process for esterifying high molecular weight polyols which minimizes depolymerization, degradation and hydrolytic cleavage as much as possible.

It is another object of the present invention to provide a process for increasing the wet and dry crease recovery 3,575,960 Patented Apr. 20, 1971 properties of a cellulosic fabric which has been esterified through a difunctional carbonic carboxylic anhydride.

Generally speaking, the present invention involves a process wherein a high molecular weight polyol, principally a cellulosic material, is esterified by treating it with a carbonic carboxylic anhydride compound having the generic formula R is an organic radical of from 1 to about 20 carbon atoms selected from the group consisting of (1) monovalent radicals selected from the class consisting of alkyl, branched alkyl, alkenyl, branched alkenyl, aralkyl, aryl, alkoxyalkyl and fluorinated counterparts of the foregoing monovalent radicals, and (2) the divalent radicals selected from the class consisting of alkylene, alkenylene, aralkenylene and arylene;

a is the integer 1 when R is selected as a monovalent radical and is the integer 2 when R is selected as a divalent radical;

G is hydrogen when R is selected as a divalent radical, and is a member selected from the group consisting of hydrogen and wherein:

where A is an organic radical of from 1 to about 20 carbon atoms selected from the group consisting of alkyl, branched alkyl, alkenyl, branched alkenyl, aralkyl, aryl, alkoxyalkyl and fluorinated counterparts of the foregoing radicals, when R is selected as a monovalent radical;

R" is an alkylene radical of from 1 to about 12 carbon atoms, and thereafter subjecting the treated polyol to mild reaction conditions until active hydrogen on said polyol is replaced by carbon acyl radicals.

Necessarily the carbon acyl radicals which replace the active hydrogen in the cellulosic material may be either of the formula when R is monovalent or of the formula -ORC-- (l it when R is divalent.

In either case, it is seen that inasmuch as the carbon acyl radicals are bonded to the carbon backbone of the polymer through the oxygen atom of the hydroxyl group, the result is an esterification of the polymer.

The net effect of the process in generalized form is shown by the following exemplary chemical equation, wherein an active site of an hydroxyl-containing polymer is denoted by H-OPol, and the simplest type of carbonic carboxylic anhydride is used (R' being lower alkyl and representing R"G, when G is hydrogen).

From the simple Equation A above it is seen that the by-products of the acylation or esterifying step are a lower alcohol and gaseous carbon dioxide, both of which are non-noxious and readily disposable.

Esters of cellulose have been Widely used and studied and have assumed an importance in industry and commerce. In these compounds the selection of the organic radical that enters the cellulose has been largely a matter of choice depending entirely upon the type of ester 3 which is desired. The present invention readily adapts itself to this broad selection of the organic radical R, thereby permitting an extensive range of desired products. Consequently, Equation A above is merely representative of reactions according to the present invention, and more complex carbonic carboxylic anhydrides within the generic formula may be used to esterify the hydroxylcontaining polymer in like manner. For purposes of clarity and for isolation of particularly unique features associated with the use of certain of the carbonic carboxyhc anhydrides in the present invention the class of such compounds represented by the generic formula given above may be broken down into three sub-generic groups, which are hereinafter designated Series I, II and III as follows:

Series I (R is monovalent, a is 1, G is H, and R"H is abbreviated below as R, a lower alkyl):

Compounds of Series I wherein RCO is acryloyl are disclosed in co-pending application Ser. No. 653,614 filed July 17, 1967. Series II (R is monovalent, a is 1, G is -O(|30]C|A and to simplify illustration here, A will be considered to be identical with R):

RCfllO-(fiOIVOC-OER O 0 Series III (R is divalent, a is 2, G is H, and R, a

lower alkyl, stands for R"H):

Many of the carbonic carboxylic anhydrides used in the process of this invention are obtainable by known methods. Generally they can be prepared by a condensation reaction between a carboxylic acid and a suitable chloroformate, the by-product hydrogen chloride immediately being neutralized in situ by an acid acceptor. As used herein and in the claims, the general terms carboxylic acid and alkyl chloroformate are understood to include dicarboxylic acids and alkylene bis(chloroform ates), respectively. Methods of preparation of carbonic carboxylic anhydrides of Series I, II and III are exemplified by the following Reactions B, C and D, respectively.

RCO-H C1-COR ECO-CR It I] HG1 H H 0 O 0 Mono- Alkyl carboxylic Ohloroformate Acid RCOH l OlCOR"OC-Cl lib-OCR I; ll ll H -2H 01 Alkylene Bis(Chlorcfcrmate) R'fiO-JflJOIV'OKflI-OFR O O O 0 R[C O-Hh 2ClCOR' R[CO-C-OR]2 I! ll 2HC1 H I! O O (D) Dicarboxylic Alkyl (III) Acid Chloroformate Considering the foregoing reactions, it is apparent that any of several series of carbonic carboxylic anhydrides may be used in the process of this invention, e.g.,

Series I from a monocarboxylic acid and an alkyl chloroforrnate,

Series II from a bis(chloroformate) and 2. molar parts of a monocarboxylic acid, and

Series III from a dicarboxylic acid and 2 molar parts of an alkyl chloroformate.

In the Tablets 1, 2 and 3 below there are shown the formulae and names of several typical carbonic carboxylic anhydrides which are useful in the present invention, and which for convenience sake have been divided into the classifications of Series I, II and III, respectively:

TABLE 1 Series I: R (6-0-(fi O R, where R is ethyl R Name of anhydride CH3 Acetic ethylearbonlc.

C H2=C H- Acrylic ethylcarbonic. C n H2a- E thylcarboru'c laurie. CIIHSfl- Ethylcarbonic stearic. CaH Benzoic ethylcarbonic.

E CsH1C Ethylearbonic neoheptanolc C Ha (3 Ha CnHmC- Ethylcarbonie neotridecanoic.

C Ha

(F C-) 2CO( 0 Hz) 10- Ethylcarbonlc 1l-[fluorobls(trifluoromethyl)methoxy1undeca- F nolc.

CH3( CH2} a-l-CH-CHrh- Ethylearbonlc (polystyrene) carboxy c. 0H5

where n is an integer TABLE 2 Series II: R%O(if-0R0O-O(3 R,

where R is CH2CH2 R Name of anhydride 0 H2=C H Ethylenebis (carbonic acrylic).

0 Ha C1H Ethylenebis (carbonic neoheptanoic) (F C-) 2CHO-CH2 Ethylenebis {carbonic [bis (trlfluoromethyl) methoxylacetic I H(F2C)sCH2O CH2C Hz- Ethylenebislcarbonie 3-(1H,1H,7H-

dodeeafluoroheptylqxy) propionic]. Ethylenebis {carbonic [fiuorobis(triwhere R is ethyl Divalent R Name of anhydride -(CH Suberie bis(ethylearbonic) (CH Adipic bis (ethylcarbonic) (CH Sebacic bis (ethylcarbonic).

wherein A is selected from the group consisting of polyfiuoroalkyl and polyfiuoroalkoxyalkyl, R" is a lower alkylene of up to 20 carbon atoms, and G is selected from the group consisting of hydrogen and Examples of suitable compounds of the novel class defined above are ethylenebis [carbonic 3-(1H,lH,7H-dodecafluoroheptyloxy) propionic anhydride] ethylenebis{carbonic [bis(trifiuoromethyl) methoxy] acetic anhydride},

ethylenebis{carbonic[fluorobis(trifluoromethyl)methoxy] acetic anhydride},

ethylcarbonic 11- [fluorobis (trifluoromethyl) methoxy] undecanoic anhydride, and

ethylenebis {carbonic 4- [fluorobis (trifiuoromethyl) methoxy]butyric anhydride}.

The preparation of the above-mentioned compounds is described with particularity in Examples 1, 2, 3, 9 and 10, respectively.

Since it is known to be difiicult to prepare mixed carbonic carboxylic anhydrides from strong acids in that such anhydrides generally lack stability and tend to decompose, it was a surprising and unexpected discovery to find that these anhydrides of fluorinated acids, as defined above, can be prepared, isolated, and effectively used for the esterification of polyhydroxylated polymers.

In general, the carbonic carboxylic anhydrides having fluorinated groups may be prepared by the condensation reaction of a polyfiuoroalkanoic acid with a diol bis(chloroformate) or alkyl chloroformate. One or more of the ingredients is usually diluted in a solvent, such as ethyl ether, and thereafter reacted in the presence of a weak base, such as triethylamine. The reaction proceeds below room temperature and it is preferably maintained at about 0 C. or below. Further particulars will be evident by reference to the examples.

The esters which have been created by the use of the novel polyfiuoro compounds defined above can be useful in the preparation of textiles of improved stain resistance and water repellency.

When practicing the process of the present invention it is generally preferred that an anhydride be selected that is relatively high-boiling. For example, in esterifying a cellulosic fabric with a carbonic carboxylic anhydride, a relatively simple technique of a one-step pad-cure may be used if the anhydride is relatively high-boiling. Esterification agents which meet this criteria and which are particularly suited to this technique are those which have been prepared from a compound that has two chloroformyloxy groups, e.g.

ClC-OROCCl a. ll

Ethylene glycol bis(chloroformate), i.e., R" is CH CH is representative of such a starting material. It has been found that such a compound can be used, for example, to prepare all of the individual esterifying agents listed in Table 2. The resulting agents are all high-boiling and suited to the simple pad-cure treatment which may be used according to the invention. The method of using a diol bis (chloroformate) as a means for preparing highboiling esterification agents which are particularly suited to the purposes of the present invention constitutes part of the present invention, and Examples l-S and 10 are exemplary of it.

Most of the compounds of Series II and III are relatively high-boiling, including all of those set forth in Tables 2 and 3; however, certain compounds within the .generic formula may be relatively low-boiling, especially those in the sub-genus Series I. If it is found by experience that the particular compound being used is not sufii ciently high-boiling to be readily applied by pad-cure techniques, then a wet reaction or immersion technique can be used on cellulosic substrate. The use of such techniques is also set forth in the examples, e.g., Example 11.

Particularly effective results are achieved when a hydroxyl-containing polymer is treated by a carbonic carboxylic anhydride, such as those defined by the subgeneric Series III, which is capable of forming cross-links with the polymer. The reaction as it applies to cellulose, for example, can be represented as follows:

The net effect is that cellulose is cross-linked by esterification with a dicarboxylic acid, such as suberic acid, adipic acid or sebacic acid. The application of this principle is that it provides an improved means for imparting crease recovery (both wet crease recovery and dry crease recovery) to cellulosic fabrics. Because no acidic catalyst is required, and because the reaction is effected under relatively mild, neutral conditions, this process permits cellulosic fabric to be modified for durable creases and pleats without significant weakening of the strength of the textile. The efficiency of the cellulose reaction with the carbonic carboxylic anhydrides prepared from dibasic acids is quite high, and in most cases approaches Similarly, carbonic carboxylic anhydrides that have a residual vinyl group after reaction with the cellulose may undergo further addition or cross-linking through the vinyl group. For example, acrylic ethylcarbonic anhydride (see Table 1) has an active vinyl group, and is useful for making acrylic esters of hydroxyl-containing polymers. Such esters can be cross-linked through addition polymerization, as the following equation denotes:

nCHz=CH CH2CH (1 0 $=O 0 Cell OCell n (where n represents the degree of polymerization).

Although one of the outstanding advantages of the present invention is that mild conditions may be used which will not degradate the substrate or polymer structure, the esterification reaction itself may be carried out over a very wide range of conditions.

Thus, the esterification may take from a few minutes to several hours, depending upon the other conditions chosen, particularly temperature. High temperatures require less time within which to effect esterification, and vice versa. In general, however, a suitable reaction may be obtained by using temperatures in the range of about 10 C. to 200 C. or even higher, and by using times in the range of about 24 hours to 5 minutes or less. Obviously the permissible range of reaction conditions is quite extensive, and the optimum conditions for any particular reaction involving a selected polymeric substrate and a selected carbonic carboxylic anhydride can be arrived at quickly in an empirical manner.

The carbonic carboxylic anhydride is preferably used while diluted in an appropriate solvent. Suitable solvents are those which are polar and hence swell the cellulosic substrate. A preferred polar solvent is N,N-dimethylformamide. Other suitable illustrative solvents are N,N-dimethylacetamide, 1-methyl-2-pyrrolidinone, 1,5-dimethyl- I-Z-pyrrolidinone, dimethyl sulfoxide and tetramethylene sulfone.

Having thus described the general process, hereinbelow are set forth several specific examples further illustrating the use of the process of the present invention and the advantages that can be derived from it. Examples 1-10 describe methods by which one may prepare novel carbonic carboxylic anhydrides which are useful in the present invention, and Examples 11-28 describe specific embodiments of the process and compounds of the present invention.

EXAIVIPLE 1 Preparation of ethylenebis [carbonic 3 (lH,lH,7H- dodecafiuoroheptyloxy) propionic anhydride] 3 (1H,1H,7H dodecafluoroheptyloxy)propionic acid (40.4 grams, 0.1 mole) was dissolved in 200 ml. of ethyl ether. The solution was cooled at C. and triethylamine (10.1 grams, 0.1 mole) was added. At 0 C. ethylene glycol bis(chloroformate) (9.35 grams, 0.05 mole) was added in minutes with stirring. Upon completion of the addition, the mixture was stirred for another minutes and allowed to warm to room temperature. The mixture was filtered to remove triethylammoniurn chloride, and the filtrate was washed with 50 ml. of a saturated solution of sodium bicarbonate, then by 50 ml. of water, and finally dried with sodium sulfate. Ethyl ether was distilled 01f in vacuo at 30 C. leaving 39 grams (an 85% yield) of ethylenebis[carbonic 3 1H,1H,7H-dodecafiuoroheptyloxy(propionic anhydride] EXAMPLE 2 Preparation of ethylenebis (carbonic [bis(trifluoromethyl) methoxy] acetic anhydride [Bis(trifluorornethyl)methoxy] acetic acid (81.4 grams, 0.36 mole), ethylene glycol bis(chloroformate) (33.7 grams, 0.18 mole), and triethylamine (36.4 grams, 0.36 mole) were allowed to react, the procedure being similar to that of Example 1. The yield of ethylenebis[carbonic (bis(trifluoromethyl)methoxy)acetic anhydride] was 78 grams (77% of the theoretical maximum amount).

EXAMPLE 3 Preparation of ethylenebis (carbonicfiluorobis(trifluoromethyl methoxy] acetic anhydride) [(F3C' )2(|] O CH290$!:OGH2 }3 F d o [Fluorobis(trifluoromethyl)methoxy] acetic acid 122 grams, 0.5 mole), ethylene glycol bis(chloroformate) (46.75 grams, 0.25 mole), and triethylamine (50.5 grams, 0.5 mole) were allowed to react, the procedure being similar to that of Example 1. The yield of ethylenebis [carbonic [fluorobis(trifluoromethyl) methoxy] acetic anhydride] was 129 grams (86%).

EXAMPLE 4 Preparation of ethylenebis (carbonic acrylic anhydride) Acrylic acid, ethylene glycol bis(chloroformate) and triethylamine in the molar proportion of 2, 1 and 2 were allowed to react, the procedure being similar to that of Example 1. The yield of ethylenebis(carbonic acrylic anhydride) was of the theoretical amount.

8 EXAMPLE 5 Preparation of ethylenebis (carbonic neoheptanoic anhydride) CH3 2C lH 3COzH [ClQOGHz-lz Neoheptanoie acid, ethylene glycol bis(chloroformate), and triethanolamine in the molar proportion of 2, 1 and 2 were allowed to react, the procedure being similar to that of Example 1. The yield of ethylenebis(carbonic neoheptanoic anhydride) was 86% EXAMPLE 6 Preparation of ethylcarbonic neoheptanoic anhydride CzHsO CC] E0 CC (CH3)2 5] HCl Preparation of ethylcarbonic neotridecanoic anhydride C2H5O (301 H0 CC (CH3)2 ll 1] l HCl 0 O CQHN C2HsO(H1O C(|3 (*"CHaM o g 09H Neotridecanoic acid, ethyl chloroformate, and triethanolarnine in equimolar proportion were allowed to react, the procedure otherwise being similar to that of Example 1. The yield of ethylcarbonic neotridecanoic anhydride was 78% EXAMPLE 8 Preparation of ethylcarbonic (polystyrene)carboxylic anhydride First, (polystyrene)carboxylic acid was prepared by the following series of reactions in which the degree of polymerization is denoted by n, and Bu stands for The solution composed of 112.5 ml. (0.975 mole) of styrene, 1500 ml. of dry benzene, and 10 ml. of tetrahydrofuran was added (under nitrogen) to a solution of 24 grams (0.39 mole) of butyllithium in 700 ml. of dry petroleum ether. The addition required 5 minutes. The reaction solution, which became dark red, was poured into a flask containing a large excess of crushed, solid carbon dioxide. The reaction mixture was allowed to warm to room temperature at which time an excess of gaseous hydrogen chloride was bubbled into the mixture during a period of 1 hour. By-product lithium chloride was filtered oil. The filtrate was concentrated considerably by evaporation. The desired product was precipitated by the addition of methanol at 20 C., collected on a filter, and dried. The yield of carboxyl-terminated polystyrene was 100 grams. The equivalent weight of (polystyrene)carboxylic acid was found to be 1810 by titration with standard base. Hence, the average degree of polymerization, n, was between 16 and 17.

Next, the carboxyl-terminated polystyrene was converted to ethylcarbonic (polystyrene)carboxylic anhydride in accordance with the following reaction.

The carboxyl-terminated polystyrene (90.5 grams, 0.05 mole) and 5.05 grams (0.05 mole) of triethylamine were dissolved in 1 liter of ethyl ether. The solution was cooled to C. To it was added 5.43 grams (0.05 mole) of ethylchloroformate dropwise in 15 minutes, while the reaction temperature was kept at 0 C. The reaction solution was allowed to stand for 2 hours and warm to room temperature. Triethylammonium chloride was filtered off. The filtrate was evaporated to dryness, resulting in a yield of 87 grams of ethylcarbonic (polystyrene)carboxylic anhydride.

'EXAMPLE 9 Preparation of ethylcarbonic 11- [fluorobis(trifiuoro methyl)methoxy] undecanoic anhydride First, 1l-[fluorobis(trifiuoromethyDmethoxy]undecanoic acid was prepared by the following reaction.

During a 30 minute period, a total of 260 grams (1.56 moles) of hexafiuoroacetone was bubbled into a mixture of 239 grams (1.56 moles) of cesium fluoride in 700 ml. of dry (bis-(2-methoxyethyl) ether at 40 C. Then the mixture was allowed to warm to room temperature, and methyl ll-bromoundecanoate (340 grams, 0.90 mole) was added promptly. The mixture was stirred at 75 C. for 48 hours. Next, the solid matter (mainly cesium bromide) was filtered off. The filtrate was washed by two separate 2-liter portions of water. Ethyl ether was added to the organic layer, which was dried over anhydrous magnesium sulfate. After removal of ethyl ether by distillation, methyl 11-[fluorobis(trifiuoromethyl)methoxy] undecanoate (300 grams) was collected mainly at 80 to 85 C. during distillation at approximately 0.1 torr. Saponification was effected by allowing the following mixture to remain for 2 hours at room temperature: 285 grams (0.74 mole) of the ester in 1 liter of ethanol (denatured by 5% of its volume of methanol), and 60 grams (1.5 moles) of sodium hydroxide dissolved in 60 ml. of water. Then the mixture was poured into 2 liters of water, and acidified with concentrated hydrochloric acid to pH 3. The oily layer was separated, dissolved in ethyl ether, and washed with water until practically neutral. The organic solution was dried over anhydrous magnesium sulfate. The solvent was volatilized off, leaving 279 grams of 1l-[fiuorobis(trifiuoromethyl) methoxy1undecanoic acid.

Next, the heptafiuoro ether-acid was converted to ethylcarbonic 1 1- [fluorobis (trifluoromethyhmethoxyl undecanoic anhydride by means of the following reaction.

A solution consisting of 219 grams (0.59 mole) of the heptafluoro ether-acid and 59.7 grams 0.59 mole) of triethylamine in 1 liter of ethyl ether was cooled to 0 C. During a 15 minute period a total of 64.3 grams (0.59 mole) of ethyl chloroformate was added dropwise at 0 C. Then the mixture was stirred for 1 hour and was allowed to warm to room temperature. Triethylammonium chloride was filtered off. The filtrate was washed with a saturated solution of sodium bicarbonate, next with water, and then dried over anhydrous sodium sulfate. After the solvent had been evaporated, the resulting yield of ethylcarbonic l 1- [fluorobis(trifiuoromethyl) methoxy] undecanoic anhydride was 234 grams.

EXAMPLE 10 Preparation of ethy1enebis[carbonic 4-[fiuorobis(trifiuoromethyl)methoxy]butyric] anhydride First, 4 [fluorobis (trifluoromethyl)methoxy1butyric acid was prepared "by the following reaction.

F Saponification Acidification A total of 350 grams (2.1 moles) of hexafiuoroacetone was bubbled into a mixture of 123 grams (2.1 moles) of potassium fluoride in 800 ml. f dry bis(2-methoxyethyl) ether at 40 C. Then the mixture was allowed to warm to room temperature and methyl 4-bromobutyrate (380 grams, 2.1 moles) was added promptly. The mixture was stirred at C. for 16 hours. After that, it was poured into 2 liters of water. The organic layer was dissolved in ethyl ether and dried over anhydrous magnesium sulfate. After removal of ethyl ether by distillation, methyl 4- [fiuorobis trifluoromethyl) methoxy] butyrate (25 6 grams) was collected mainly at C. during distillation at approximately 10 torrs. Saponification was effected by stirring the following mixture for 1.5 hours at room temperature: 256 grams (0.895 mole) of the ester in 2 liters of methanol, and 72 grams (1.8 moles) of sodium hydroxide dissolved in 72 grams of water. Then the mixture was poured into 4 liters of water, and acidified with concentrated hydrochloric acid to pH 3. The oily product was dissolved in ethyl ether, and washed with Water until practically neutral. The organic solution was dried over anhydrous magnesium sulfate. The solvent was volatilized off, and a total of 195 grams (0.717 mole) of 4-[fluorobis (trifluoromethyl)methoxy]butyric acid was collected at C. during distillation at 2 torrs.

Next, the heptafiuoro ether-acid was converted to ethylenebis[carbonic 4 [fluorobis(trifiuoromethyl)methoxyl butyric anhydride] by means of the following reaction.

A solution consisting of grams (0.68 mole) of the heptafiuoro ether-acid and 68.7 grams (0.68 mole) of triethylamine in 1.5 liters of ethyl ether was cooled to 0 C. During a 15 minute period a total of 65.5 grams (0.35 mole) of ethylene glycol bis(chlorof0rmate) was added dropwise at 0 C. Then the mixture was stirred for 1 hour and was allowed to warm to room temperature. Triethylammonium chloride was filtered off. The filtrate was washed with a saturated solution of sodium bicarbonate, next with water, and then dried over anhydrous sodium sulfate. After the solvent had been evaporated, the resulting yield of ethylenebis[carbonic 4-[fiuorobis(trifluoromethyl)methoxy]butyric anhydride] was 200 grams.

Having thus set forth exemplary procedures for the preparation of carbonic carboxylic anhydrides, there is shown in the examples below how such carbonic carboxylic anhydride compounds, as well as others, can be used according to the invention to esterify cellulosic materials.

polymerized ethylene oxide). After having been dried, the samples were conditioned and weighed. Weight gains for lla and 11!) resulting from acetylation were, respectively, 5.3 and 6.1%, corrected for moisture regain. In the warp direction, tensile strengths were respectively The tests which are used in the examples to show 58 and 54 pounds. The tensile strength of untreated 80 x the relative physical changes which have occurred by 80 print cloth was 59 pounds in the warp direction, conreason of the esterification reactions, and the units and sequently there was no substantial loss in strength associlegends used therein, are as follows: ated with the estenfication.

Crease recovery angle, in degrees, total of readings in I filling (F) and warp (W); Monsanto Method, ASTM EXAMPLE 12 D I A sample of 80 x 80 cotton print cloth was conditioned Stifiness (cantilever), 1n milligrams per centlmeterg and Weighed as in Example Then it was Padded with A TM D1 a 20% solution of acrylic ethylcarbonic anhydride in T ear Strength, in Pounds Warp dlrectlon, 15 dimethylformamide. Rollers on the laboratory padder mendol'f Method, ASTM f were set so the resulting wet pick-up was 92%. Without Tensile strength, in pounds inwarp (W) direction, ravel drying, the Sample was placed in a test tube, which was 1 inch strip method; Federal Specifications for Textile Sealed and kept f 4 hours in a Water bath at 93 Aft r Test Methods, CCCT-191b, Method the treatment, the sample was rinsed, conditioned and The conditioning of samples for testlng purposes was Weighed as those Steps were i d gut i E l 11, at 21i1 C. and a relfltlve humldlty of 65i2%- In the The weight gain, corrected for moisture regain, was 1.7%, tables Presenting data all parts and Percentages are by indicative that 24% of the amount of reagent added on v I I n p weight unless otherwlse noted. the fabric had undergone chemical reaction to form an The following legends have been used: li ester f c llulos OWB: On the weight of the bath used for paddmg, in 25 percent. EXAMPLE 13 OWF: On the weight of the fiber (or fabric), i.e., the percentage based on the weight of the fabric prior to Three samples of 80 X 80 coiton Pnut deslgnatejd 13a, 13b and 13c, were conditioned and Weighed as 1n padding. OWB times WPU/ 100% OWF.

WPU: Wet pickup, i.e., the percentage of wet add-on Example Then they w Paddfid W? a 20% OWF, measured directly after padding. tion of ethylcarbonic lauric anhydride 1n dimethylforma- Moisture regain (in percent) is the weight of moisture In accordance with Percentages Shown m the calculated as a percentage of the bone-dry weight, ASTM lowing m Samples and cured at 135 C. for various times as indicated in Table 4. After the Extent of utilization of padded reagent (percent) is the heat treatments, each sample was rinsed, conditioned and eificiency of reaction calculated as weighed as those steps were described in Example 11.

The data obtained, including the physical performance f( results of the esterified (lauric) cellulose are shown in (Percent, OWF)e Table 4.

TABLE 4 Ethylcarbonic lauric anhy- Extent utili- Crease dride percent, from di- Corrected zation of recovery, methylformamide weight padded degrees Tensile Tear gain, reagent, strength, strength, Smple OWB WPU OWF Conditions for esterification percent percent Dry Wet lbs. lbs

20 84 16. 8 4 hours at, 90 C l. 1 9 20 90 18.0 0.25 hour at 135 0 s. 9 53 22s 19s 52 1. s 20 as 17.6 0.5 hour at 135 0 7.2 66 214 205 56 1. 5 Untreated Average results on 6 specimens 193 162 59 1. 7

where f is the found or observed weight gain, e is the equivalent Weight of the residue of atoms acylating the cellulose, E is the equivalent weight of the carbonic carboxylic anhydride, and OWF is defined as above.

EXAMPLE 11 The following reaction was carried out to make an acetylated cellulose:

Cello-$0113 CO H-O C 11;

Greater yields were obtained for the treatments at 135 C. than for that at 90 C. Despite the fact that the extents of the utilization of the reagent padded on the fabric were appreciable (5 8 and 66%), mechanical strength values were not greatly impaired as compared with the untreated control specimens. On the other hand, crease recovery was significantly improved in comparison with the untreated (control) specimens.

EXAMPLE 14 Three samples of x 80 cotton print cloth, 14a, 14b and 14c, were conditioned and weighed as in Example 11. Then they were padded with a 20% solution of ethylcarbonic stearic anhydride in dimethylformamide in accordance with percentages shown in the folowing Table 5. Sample 14a was kept wet in a sealed test tube at C. for 4 hours. The other samples were cured at C. for various times as indicated in Table 5. After the various heat treatments, each sample was rinsed, conditioned and weighed as those steps were described in Example 11. The treatments formed stearic esters of cellulose, and the remaining pertinent data, including the results of evaluation of performance, are shown in Table 5.

It is seen that the esterified cellulose showed significantly improved crease recovery with no significant loss in tear strength. Moreover, the esterified cellulose was characterized by a softer hand, as may be seen by the reduced carbonic neoheptanoic anhydride in dimethylformamide stiffness. for 4 hours at 90 C. After the various heat treatments,

TABLE 5 Ethylcarbonie stearie an- Extent utili- Crease hydride percent, from (11- Corrected zation of recovery, methyli'ormamide weight padded degrees Tear gain, reagent, strength, Stifiness, Sample OWB WPU OWF Conditions for esterification percent percent Dry Wet lbs. mg./crn

20 73 14. 6 4 hours at 90 C 1. 1 20 72 14. 4 0.25 hour at 135 C 7. 4 75 228 196 1. 9 75 20 72 14. 4 0.5 hour at 135' C 7. 4 75 214 205 1. 4 75 Untreated Average results on 5 specimens 193 162 1. 7 105 EXAMPLE each sample was rinsed, conditioned, and weighed as those Three samples of 80 x 80 cotton print cloth, 15a, 15b 15 steps were described in Example 11. Extents of esterificaand 150, were conditioned and weighed as in Example 11. tion to form neoheptanoic esters of the cellulose are shown Then they were padded with a solution of benzoic in Table 7.

TABLE 7 Ethylcarbonic neoheptanoic anhydride percent, from dimeth- Corrected Extent utiliylformamide weight zation of Conditions for gain, perpadded rea- Sample OWB WPU OWF esterification cent gent, percent 20 90 18.0 4 hours at 90 C 0. 6 20 85 17.0 0.25 hours at 121 C 2. 3 10 81 8.1 0.25 hour at; 135 C 1. 7 37 25 (Not padded; 4 hours at 90 C 4.0

immersed) ethylcarbonic anhydride in dimethylformamide in accord- EXAMPLE 17 ance with percentages shown in the folowing Table 6. Sample 15a was kept wet in a sealed test tube at 90 C. for 4 hours. The other samples were cured at 135 C. for various times as indicated in Table 6. After the various heat treatments, each sample was rinsed, conditioned and weighed as those steps were described in Example 11.

The process resulted in the formation of benzoic esters Three samples of 80 x 80 cotton print cloth, 17a, 17b,

and 170, were conditioned and weighed as in Example 11. Two of them 17a and 17b) were padded with a 20% solution of ethylcarbonic neotridccanoic anhydride (the product of Example 7) in dimethylformamide in accordance with data tabulated below in Table 8. Sample 17a was kept wet in a sealed test tube at 90 C. for 4 hours.

of cellulose, the extent of esterication being somewhat s k 1171; was cured for 2 5 h at 135 Sample higher for the samples treated at 135 C. 4 170 was immersed in a 25% solution of ethylcarbonic TABLE 6 Benzoic ethylcarbonic anhydride percent, from dimethyli'ormam- Corrected Extent utililde weight zation of Conditions for gain, perpadded rea- Sarnple OWB WPU OWF esterification cent gent, percent 20 88 17. 6 4 hours at 90 C 2. 6 28 20 94 18. 8 0.25 hours at 135 C 5. 8 57 20 88 17. 0 0.5 hours at 135 0.-.. 5. 7 61 EXAMPLE 16 neotridecanoic anhydride in dimethylformamide for 4 Four samples of 80 x 80 cotton print cloth, 16a, 16b, hours at 90 C. After the heat treatment, each sample 160 and 16d, were conditioned and weighed as in Example was rinsed, conditioned and weighed as those steps were 11. Three of them, 16a, 16b, 160, were padded with a described in Example 11. The treatment resulted in forsolution of ethyl-carbonic neoheptanoic anhydride (the mation of neotridecanoic esters of cellulose. Results are product of Example 6) in dimcthylformarnide and treated given in Table 8 below.

TABLE 8 Ethylcarbonie neotridecanoic anhydride percent, in dimethyl- Corrected Extent utiliiormamide weight zation of Conditions for gain, perpadded rea- Sample OWB WPU OWF esterification cent gent, percent 20 67 13. 4 4 hours at 90 C 1. 6 14 20 13.0 0.25 hour at 135 C 1.7 18 25 (Not padded; 4 hours at 90 C 1. 6

immersed) and tested in accordance with the data tabulated below EXAMPLE 18 in Table 7. Sample 16a was kept wet in a sealed test tube Three samples of x 80 cotton print cloth, 18a, 18b at C. for 4 hours. Samples 16b and 160 were cured and 18c, were conditioned and weighed as in Example at 121 C. and C. for 15 minutes, as indicated. 11. Two of them (18a and 18b) were padded wi-tha 25% Sample 160. was immersed in a 25% solution of ethyl- 75 solution of ethylenebis (carbonic acrylic anhydride), the

of cellulose. Physical testing of the padded samples showed 10 20b improved crease recovery with but slight loss in tensile strength.

show formation of [bis(trifiuoromethyl)methoxy]acetic esters of cellulose.

TAB LE 11 Anhydride of Example 2, percent, in Corrected dimethylformamide weight Conditions for gain, Sample OWB WPU OWF esterification percent 20:: 20 95 19. 0. 25 hour at 135 C. 0. 62 20 90 18.0 0.5 hour at 135 C 0. 58 20 (Not padded; 4 hours at 90 C O. 39

immersed) TABLE 9 Ethylenebis (carbonic Extent Crease acrylic anhydride) percent, Corrected utilization recovery,

in dimethylformamide weight of paded degrees Tensile Conditions for gain, reagent, strength, Sample OWB WPU OWF esterification percent percent Wet Dry lbs.

25 83 20. 7 0.25 hour at 135 C 4. 0 46 230 232 47 25 82 20. 5 0.5 hour at 135 C. 4. 4 51 233 225 44 (Not padded; 4 hours at 90 C. 2. 6

immersed) EXAMPLE l9 EXAMPLE 21 Four samples of 80 x 80 cotton print cloth, 21a, 21b, 21c and 21d, were conditioned and weighed as in Example 11. Three of them (21a, 21b, 210) were padded With a 20% solution of ethylenebis[carbonic 3 (lH,lH,

0 7H dodecafiuoroheptyloxy)propionic anhydride], the

product of Example 1, in dimethylformamide, and cured in accordance with data tabulated below in Table 12. The fourth sample (21d) was immersed in a 20% solur tion of the same anhydride in dimethylformamide for 4 0 hours at 90 C. After the esterification reaction, each sample was rinsed, conditioned and weighed as in Example 11. The results tabulated below, show formation of 3- TABLE 10 Ethylenebis (carbonic necheptanoic Extent Crease anhydride) percent, in Corrected utilization recovery,

dimethylformamide weight padded degrees Tensile Conditions for gain, reagent, strength, Sample OWB WPU OWF esterification percent percent Dry Wet lbs.

1911 83 20. 7 0.25 hour at 135 C l. (l 9 202 207 19b 25 79 19. 7 0.5 hour at- 135 C 1. 1 10 202 205 55 EXAMPLE 20 Three samples of 80 x 80 cotton print cloth, 20a, 20b and 200, were conditioned and weighed as in Example ll. Two of them (20a and 20b) were padded with 50 (1H,1H,7H dodecafluoroheptyloxy)propionic esters of cellulose.

Examination of esterified sample 211) showed a fluorine content of 3.8

TABLE 12 Anhydride of Example 1, percent, in dimethylform- Corrected Extent utilizaamide weight tion of padded Tensile Conditions for gain, reagent, strength, Sample OWB WPU OWF esterification percent percent lbs.

21a 20 104 20. 8 0.25 hours at 135 C 8. 14 47 21b 20 101 10. 2 0.5 hours at 135 C 8. 13 48 56 21c 20 98 19. 6 0.25 hours at 163 C 7.87 48 21a! 20 (Not padded; 4 hours at 90 C L 0 immersed) EXAMPLE 22 a 20% solution of ethylenebis (carbonic[bis(trifluoromethyl)methoxy]acctic anhydride), the product of Example 2, in dimethylformamide, and cured, all in accordance with data tabulated below in Table 11. The third sample (200) was immersed in a 20% solution of the same anhydride in dimethylformamide for 4 hours at 90 C. After the esterification reaction, each sample was rinsed, conditioned and weighed as those steps were described in Example 11. The results, tabulated below,

Two samples of 80 X 80 cotton print cloth, 22a and 22b, were conditioned and weighed as in Example 11.

They were padded with a 25% solution of suberic bisrinsed, conditioned and weighed as in Example 11. All of 1 7 the suberoyl part of the carbonic carboxylic anhydride padded on both samples acylated the cellulose, i.e., there was 100% utilization of the reagent padded on the fabric, based on weight gains. Results tabulated below show that crease recovery angles were increased markedly above the control values of 193 C. (dry) and 162 C. (wet).

18 ous solution of sodium hydroxide (2% and it was dried for 16 hours at 50 C. in vacuo (under 1 torr). Accurately weighed samples, each approximately 4.7 grams, were kept for 20 hours in dimethylforrnamide H11. per gram of cotton) in order to pre-swell them. Then benzoic ethylcarbonic anhydride (1 to 4 grams per gram of cotton) was TABLE 13 Suberic bis-(ethylcarbonic anhydride) percent, in Corrected Extent utiliza- Crease redimethylformannde weight tion of padded covery, degrees Tensile Conditions for gain, reagent, m strength, Sample OWB WPU OWF esterification percent percent Dry Wet lbs.

22a 25 91 22.7 0.25 hour at 135C 13.5 100 281 260 36 22b 25 86 21.5 0.5 hour at 135 C 12.3 100 288 268 40 EXAMPLE 23 added to each of three samples 25a, 25b, 250) in the Four samples of 80 x 80 cotton print cloth, 23a, 23b, 23c and 23a, were conditioned and weighed as in Example 11. Two of them (23a and 2312) were kept wet with a 25% solution of adipic bis(ethylcarbonic anhydride) in a sealed test tube for various times and temperatures as shown in Table 14 below. The remaining two samples, 230 and 23d, were padded with the 25% solution and then were heat treated for the times and temperatures amounts set forth in Table 16 below. The benzoylation of the cellulose was carried out at 114:4 C. for 1.25:0.25 hour. The treated yarn was washed with methanol, and oven-dried. The degree of substitution of cellulosic hydroxyl by benzoyl, i.e., the degree of esterification or benzoylation, was calculated from the weight gain on a bone-dry basis. Results are given in Table 16.

indicated in Table 14. After the reaction period, wherein TABLE 16 each sample was subjected to conditions for formation Gramsofbenzoic Ext ent of adipic esters of cellulose, and subsequent cross-linking, ififiglfgggfigf 2 5i? gfif g g g gggggg each sample was rinsed, conditioned and weighed as in Sample gram of tt percent y benzvyl p n Example 11. The results tabulated below in Table 14 1 93 0.144 113 show that grood crease recovery angles resulted by the 2 %g g. 12%

use of this carbonic carboxylic anhydride which provides adipoyl radicals capable of cross-linking the cellulose.

The results below also show that although the acylation proceeds fairly rapidly at higher temperatures, it may also be accomplished at much reduced temperatures Variations were carried out which showed that the degree of substitution by benzoyl was not substantially affected by (a) varying the dimethylformamide-to-cotton for longer periods of time. ratio (from 3 to 12 ml. of dimethylformamide per gram TABLE 14 Adipic bis(ethylcarbonlc Extent Crease anhydride) percent, in Corrected utilization recovery, dimethyliormamide weight of padded degrees Conditions for gain, reageant, OWB WPU OWF esterification percent percent Dry Wet 25 91 22. 3 24 hours at 22 C 0. 4 5 25 88 22.0 4 hours at 90 C 1. 4 17 25 101 25. 3 0.25 hour at 135 C- 6. 3 66 246 228 25 93 23.3 0.5 hour at 135 C 5. 5 62 248 222 EXAMPLE 24 of cotton), (b) pre-swelling time, or (c) increasing the Two samples of 80 x 80 cotton print cloth, 24a and 24b, were conditioned and weighed as in Example 11. They were padded with a 25% solution of sebacic bis(ethylcarbonic anhydride) in dimethylformamide and cured (heat treated) at 135 C. for various times as tabulated below in Table 15. After the reaction, which took place under conditions promoting acylation and cross-linking, each sample was rinsed, conditioned and Weighed as in Example 11. Practically all of the sebacoyl part of the carbonic carboxylic anhydride padded on both samples acylated the cellulose, i.e., there was 97-98% utilization of the reagent padded on the fabric, based on weight gains. Results tabulated below show high crease recovery angles, even at a high tensile strength relative to the control specimens.

A sample of x 80 cotton print cloth was conditioned and weighed as in Example 11. It was padded with a 20% solution of ethylcarbonic (polystyrene) carboxylic anhydride (the product of Example 8) in dimethylformamide so the wet pick-up was 91%. The sample was dried at 50 C., then cured for 0.25 hour at C. Next it was rinsed in toluene, in dimethylformamide, and final- TABLE 15 Sebacic bis(ethylcarbonic Extent Crease anhydride) percent, in Corrected utilization recovery,

dtmethyltormamide weight of padded degrees Tensile gain, reageant, strength,

Sample OWB WPU OWF Conditions for esterification percent percent Dry lbs.

24a 25 79 19. 7 0.25 hr. at 135 C 9. 18 97 284 255 38 24b 74 18. 5 0.5 hr. at 135 C 8. 72 98 289 252 57 Control Untreated Average results on 5 specimens 193 162 59 EXAMPLE 25 Single-ply cotton yarn was selected of such a size that a 15,540 yard length of it weighed a pound. It was purified ly in a 0.1% aqueous solution of the nonionic detergent used in Example 11. Despite the action of the strong solvents and detergent, a permanent weight gain of 1.12%

by extraction with ethanol and by scouring with an aque- 75 persisted, indicating that esterification had occurred.

19 EXAMPLE 27 with a carbonic carboxylic anhydride compound defined by the formula Rl:- (I? o-tp: o R"G:|

O G a wherein R is polystyryl or an organic radical of from 1 to about 20 carbon atoms selected from the group consisting bis(trifluoromethyl)methoxy]undecanoic esters of cellulose. After the esterificaton reaction, each sample was of U? monovalent radllal li l i kfrorlnghe chars; rinsed in dimethylformamide and in water. Conslstmg of alkyl i i a 3 p Results of measurements of the several samples are alkenyl alalkyl fi a 9 y gi tabulated below in Table 17. counterparts of t e oregomg monova ent ra rca s, Examination of sample 27a showed it had a boundand I a dlvalent radical Selected from the class fluorine content of 2.98%. Sample 27a was thereafter exconslstlilg of alkylene alkenylene) aralkenyl and posed to 0.5 normal sodium hydroxide for 3 hours at f room temperature, with the result that a weight loss of a 15 i mtegef 1 R 15 Selficted a monovalent 1.94% occurred. The loss of reagent was 29% from alkarefdlcal and the Integer 2 when R 15 Selected as a line hydrolysis, and the resulting fabric sample was found 0 dlvalem Iadlcal; to have a fluorine content of 2.00%. G is hydrogen when R is selected as a divalent radical,

TABLE 17 Anhydride reagent (C11HZ5F1O5) percent, from Weight Extent dimethylformamide gain utilization Tensile Conditions for found of reagent strength Sample OWB WPU OWF esteritlcation percent percent lbs.

20 94 18.8 025m. at 135C 7.12 48 53 20 94 18.8 7.68 51 52- 20 94 18.8 7.64 51 52 10 91 at 4.30 59 55 10 91 9.1 4.46 62 52 10 91 9.1 4. 76 66 51 EXAMPLE 28 and is a member selected from the group consisting A sample of 80 x 80 cotton print cloth was conditioned of hydrogen and and Weighed as in Example 11. It was padded with a 20% solution of ethylenebisIcarbonic 4 [fluorobis(tr1- O fluoromethynmethoxy]butync anhydnde] Where A is an organic radical of from 1 to about 20 (C H F O carbon atoms selected from the group consisting of alkyl, branched alkyl, alkenyl, branched alkenyl, 3, g ifgg j f g ggi i g z zgsifixg i gZ aralkyl, aryl, alkoxyalityl and fluorina ted counterparts hour at approximately 163 C. Next it was rinsed in digf i gfi g gi g gg g when R 15 selectfid as a methylformamide, then in a 0.1% aqueous solution of the nonionic detergent used in Example 11. When dry, the R 22 alkylene radlcal of from 1 to about carbon Welght gam was found to be Indicating that the under substantially neutral un-catalyzed conditions for a efficiency in the utilization of the anhydride reagent in the formation of esterified cellulose had been 17%. The bound-fluorine content of the fabric samples was 1.31%.

From the above description and representative examples of the present invention, it is seen that the carbonic carboxylic anhydrides esterify high molecular weight polyols, such as cellulose, effectively under mild, practically neutral, conditions. No catalysts are needed, and heating is minimal compared with prior practices for esterifying cellulose and the like. The process does not involve fixed acids or strong acids, and such acids are neither needed nor produced. Consequently, undesirable side effects are greatly minimized, notably depolymerization, degradation, and hydrolytic cleavage. Accordingly, the present process permits the ready preparation of valuable esters of cellulose yet avoids much of the damage to the substrate formerly connected with the modification of hydroxylated polymers by esterification.

It is understood that the above description of my invention is exemplary, and that modifications could readily be suggested by those skilled in the art to the specific processes described without departing from the spirit of the invention.

What 1 claim is:

1. The process for esterifying a hydroxyl-containing cellulosic material comprising contacting said material time and temperature sufficient to efiect acylation of said material and thereafter recovering the esterified product.

2. The process according to claim 1 wherein said carbonic carboxylic anhydride compound is selected from bis(carbonic neoheptanoic) anhydride, ethylenebis{car bonic bis trifluoromethyl)methoxy]acetic} anhydride, ethylenebis [carbonic 3-(1H,lH,7H-dodecafiuoroheptyloxy)propionic] anhydride, ethylenebis {carbonic[fluorobis(trifluoromethyl)methoxy]acetic} anhydride, ethylenebis[carbonic 4 [fluorobis(trifluoromethyl)methoxy]butyric anhydride, suberic bis(ethy1carbonic) anhydride, adipic bis(ethylcarbonic) anhydride, and sebacic bis(ethylcarbonic) anhydride.

4. The process according to claim 1 wherein the temperature during acylation is maintained between about 10 C. and 200 C. for a period of from about minutes to 24 hours.

5. The process according to claim 1 wherein the carbonic carboxylic anhydride compound is dissolved in a polar solvent when brought into contact with said cellulosic material.

6. The process according to claim 5 wherein the polar solvent is N,N-dimethylformamide.

7. The method of esterifying a hydroxyl-containing cellulosic fabric to enhance its crease recovery characteristics comprising treating said fabric with a carbonic carboxylic compound defined by the formula t ll t t wherein R has the definition given in claim 1, and R is a lower alkyl rdical having from 1 to about 12 carbon atoms, and heating said treated fabric under substantially neutral un-catalyzed conditions until at least a portion of said compound has cross-linked with the cellulose in said fabric.

8. The process according to claim 1 wherein the carbonic carboxylic anhydride compound is a relatively high boiling compound prepared from the condensation reaction product of a carboxylic acid and a diol bis(chloroformate).

9. The process according to claim 1 wherein said carbonic carboxylic anhydride compound is selected from the class consisting of 10. The process according to claim 1, wherein said hydroxyl-containing cellulosic material is a cellulosic textile material.

11. The process according to claim 10 wherein the cellulosic textile material is a fabric.

12. The process according to claim 11 wherein the carbonic carboxylic anhydride compound is contacted with said fabric by padding a solution of said compound onto said fabric.

13. The process according to claim 10 wherein the cellulosic textile material is a yarn.

14. The process according to claim 10 wherein said carbonic carboxylic anhydride compound is contacted with said cellulosic textile material by immersion of said cellulosic textile material in a solution of said compound.

15. The process of esterifying a hydroxyl-containing cellulosic material comprising contacting said material with a mixed carbonic carboxylic anhydride compound derived from the reaction of a carboxylic acid and an alkyl chloroformate, acylating the cellulose in said material by said compound under substantially neutral uncatalyzed conditions, and thereafter recovering the esterified cellulosic material.

References Cited UNITED STATES PATENTS 2,172,475 9/1939 Kaase et al 8-120 2,358,387 9/1944 Dreyfus et a1. 260 -225 2,668,168 2/1954 Pikl 260-224 3,388,072 6/1968 Domba 260-913 FOREIGN PATENTS 664,850 6/1963 Canada 117139.4

OTHER REFERENCES Malm et 211., Industrial and Engineering Chemistry, vol. 32, No. 3, March 1940, pages 405-408.

DONALD E. CZAIA, Primary Examiner R. W. GRIFFIN, Assistant Examiner US. Cl. X.R. 8120; 117139.4; 260225 

